#include <Arduino.h>

void setup()
{
  Serial.begin(115200);
  pinMode(13, OUTPUT);
  pinMode(12, OUTPUT);
}

void loop()
{
  Serial.println("Hello World!");
  digitalWrite(13, HIGH);
  digitalWrite(12, LOW);
  delay(500);
  digitalWrite(13, LOW);
  digitalWrite(12, HIGH);
  delay(500);
}
